If i didn't know better Id say radioactive material of some kind.
SAN CLEMENTE, Calif. (AP) — A woman suffered third-degree burns after what appeared to be the spontaneous combustion of rocks that had been scooped up from a Southern California beach, a fire official said. The 43-year-old woman's children collected the rocks Saturday at San Clemente Beach, and she tucked them into the pocket of her shorts, according to the Orange County Register.